Coriolis mass flowmeter

Abstract

A Coriolis mass flowmeter with at least four bent measuring tubes, at least one actuator assembly and at least one sensor assembly, wherein a first measuring tube and a second measuring tube are located in a common first plane and a third measuring tube and a fourth measuring tube are located in a common second plane, wherein the first plane and the second plane run parallel to one another, and wherein all four measuring tubes are joined together in terms of flow on the input side and on the output side with a collector. A Coriolis mass flowmeter for large amounts of flow, which is improved in respect to its measurement accuracy, is implemented in that the geometry and/or the surface characteristics of the measuring tubes are set so that the tube flow resistance of all four measuring tubes is identical.

What is claimed is: 
     
       1. Coriolis mass flowmeter, comprising:
 at least four bent measuring tubes having an inner surface with a predefined geometry and surface characteristics at least one actuator assembly and at least one sensor assembly, 
 a first measuring tube and a second measuring tube located in a common first plane, a third measuring tube and a fourth measuring tube located in a common second plane that is parallel to said common first plan, 
 and a respective flow collector joining all four of said measuring tubes together at a flow input end and at a flow output end thereof, wherein each flow collector has a chamber into which openings of all four of the measuring tubes open, 
 wherein at least one of the geometry and the surface characteristics of the inner surface of the measuring tubes has been set to produce a tube flow resistance of all four measuring tubes that is identical, and 
 wherein said at least four bent measuring tubes are all bent in the same directions. 
 
     
     
       2. Coriolis mass flowmeter according to  claim 1 , wherein the measuring tubes located in the common first plane have the same length and the measuring tubes located in the common second plane have the same length. 
     
     
       3. Coriolis mass flowmeter according to  claim 2 , wherein the bending radii of the measuring tubes located in each of the common first and second planes alternately complement one another so that the length of the measuring tubes in the respective plane is identical. 
     
     
       4. Coriolis mass flowmeter according to  claim 1 , wherein the measuring tubes located in the common first plane have different lengths and the measuring tubes located in the common second plane have different lengths, wherein the diameter of a longer of measuring tubes in each plane is greater than the diameter of the shorter measuring tubes by an amount acting to equalize the tube flow resistances. 
     
     
       5. Coriolis mass flowmeter according to  claim 1 , wherein the measuring tubes located in the common first plane have different lengths and the measuring tubes located in the common second plane have different lengths, wherein the inner surface of at least one of the shorter of the measuring tubes and the longer measuring tubes in each plane has a roughness acting to equalize the tube flow resistances. 
     
     
       6. Coriolis mass flowmeter according to  claim 1 , wherein holding devices are provided for affixing at least one the at least one actuator assembly and the at least one sensor assembly to the measuring tubes, the holding devices joining the measuring tubes located in each said plane to one another. 
     
     
       7. Coriolis mass flowmeter according to  claim 6 , wherein the holding devices are symmetrical in respect to at least two planes that are orthogonal to one another. 
     
     
       8. Coriolis mass flowmeter according to  claim 6 , wherein a part of the respective actuator assembly or sensor assembly is attached to a respective holding device above and below the measuring tubes joined by the holding device. 
     
     
       9. Coriolis mass flowmeter according to  claim 1 , further comprising node plates joining all four measuring tubes together on each of the input side and the output side thereof, the node plates being spaced apart from one another. 
     
     
       10. Coriolis mass flowmeter according to  claim 9 , wherein the collectors form the node plates. 
     
     
       11. Coriolis mass flowmeter according to  claim 1 , wherein a reinforcing element is located within a housing of the Coriolis mass flowmeter, wherein the reinforcing element has an arch-shape which runs opposite to an arch-shaped portion of the measuring tubes at which it is attached. 
     
     
       12. Coriolis mass flowmeter according to  claim 11 , wherein a closed volume is formed inside of the reinforcing element, and wherein a heat transfer medium is circulatable through the reinforcing element.